This... may help. I'll try these suggestions. It's obviously difficult to explain, after reading your posts, but I see what both of you are saying. Thanks for the replies.
edit: i know what i need to do. i was going to explain how i'll compensate for what i'm doing "wrong" :-), but it IS complicated to explain, so I can't do it adequately enough. But thanks anyway for the enlightenment!
[This message has been edited by mysteryperfecta (edited August 20, 2001).]
hmm.. i think i get what you want to do: make a large room, place your box inside that room but instead of flipping the faces in mode f4 subtract it with the subtract boolean in mode f5 (shortcut is S), then you can tunnel through it with the union boolean; Make your tunnel, through the inside of your newly made box then union it to your current mesh, this should produce your tunnel..